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I recently bought a manual 1986 325es with 200k+ miles to pretty much fix up and learn in the process. The car ran well at the beginning but then after stalling it a couple of times it would not start. As I turn the key the engine turns but doesn't start. It has fuel and batteries work since every electrical part works. I have been reading up on the forum but I don't know where to start since it seems like a general problem. Is it the fuel pump, fuel line, relays, fuses?

So when I turn the key to start the engine turns but doesn't stay on. If I keep my foot on the clutch and gas it I can keep it running but as soon as I let go the car stops. The car has been sitting like this for a couple of days now and I'm pretty sure that's not good. The first time this happened I tried doing a rolling start which also didn't work and I had to call the triple A to get it towed but by the time I got to talk to a person my friend tried one more time and the car started. I took it home and the next time I tried starting the problem showed up.

As I turn the key the car starts as in the RPM goes up just like when you start your car but then drops and the car stalls. As I mentioned this can be mitigated by holding on to the clutch and gasing bit by bit to keep the car from stalling. Once the clutch is let go the car turns off also. Hope this explains is better.

sounds like a fuel pressure problem. first change your fuel filter, then test. now, you do have 2 fuel pumps. if the intank pump is working, youll have pressure, but low pressure, if i remember correctly, 4-6psi. but its a high volume pump, 55 lpm. the second is a high pressure low volume pump, so it runs up to 45 psi but like 10 lpm. liters per minute number can be wrong and probably are, it just gets the point across.

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I know a lot about cars. I can look at a car's headlights and tell you exactly which way it's coming

Yes I will have to agree with Downhiller on this one. Spark is assumed since the engine does fire and run for a little.

Check both pumps for power. You might want to check what pressure of fuel you are seeing at the fuel rail also. I think those engines should be realizing aroud 2.5 bar of pressure at the rail iirc? Someone correct me if im wrong. If there isnt that much pressure there, then a bad pump is suspect or there is a clogged fuel filter or blocked hard line, etc...

Thank you guys both very much, first time and downhiller . I am on a business trip currently so I cant do anything until I get back. But I will as soon as I am back and will update with the results. Really want to get this thing running again.

Changing the fuel filter seems easy enough. But how do I check the fuel pumps and fuel pressure? I read from a DIY that you can check if the fuel pump is working by turning the car key all the way to before the step of turning it on, and then someone else has to listen to the pump which is under the rear passenger. I tried that by myself but no luck in hearing anything. Do you guys have a certain procedure for checking the fuel pressure for both pumps?

Well you can check for power at both pumps by using a multimeter set on the DC setting. There should be 12V being supplied to both pumps when the key is switched to the on (last position before start) position.

If both pumps are recieving power the. You know the fuel relay is up to par. Next you should hook up a pressure gauge in-line with the FPR vacuum hose disconnected to see what psi reading you are getting. Earlier instated these cars have 2.5 bar FPR's i could be wrong and they may have 3.0 Bar FPR's or right around 43psi. If you are experiencing anything below 40psi I would suspect one pump is malfunctioning. Being that there are two pumps on these cars, both would need to work together to supply the engine with enough fuel. It is possible that one pump could allow the car to run albeit very poorly.

You also can be running into the possiblity that something is clogging your fuel system. You know the youngest E30 is a rather old car (20 years old) so rust build up and other debris is floating around in the tank im sure. It could be very possible that some pieces have lodged themselves into the pump and or fuel lines ( and fuel filter) somewhere in the system.

So I finally got back home to work on the car. Just changed the fuel relay. I had to jump the car since it was non operation for a couple of weeks. So it did not start at first, this is after about 15-20 min of charge. But after 10 more minutes the car started fine, I kept it on for about 10 more minutes. Tried turning it off and on again and it would not start anymore. It seemed like there was just not enough charge. So I jumped it again, this time again while being jumped after 5-10 min it started. So I disconnected the jumper cables and let the car run for 30 mins. After 30 min I turned of the car to see if it turns on again. The car did not turn again after 30 min of charge. It seems like all the other electronics work, such as the headlights, lights inside, wipers, etc... But the car doesnt start unless it is concurrently being jumped. Is this just a problem of a bad old battery? or something else. You guy's help is much appreciated.

LOAD test the battery AND alternator. Most likely the battery. Pull it out and take it to a parts store. Just about all of them will test it for free, but make sure they actually LOAD test it, not just check it for 12v. Voltage means nothing if it has no amperage capacity.

Sounds like the car will be fine once you get the charging issue sorted.

So spark is assumed? did you try and test for spark? My E30 was just out for a couple of days because its crank sensor was dirty and it was keeping the engine from sparking like it should. after I cleaned it and reinstalled it the car sprung back to life

So spark is assumed? did you try and test for spark? My E30 was just out for a couple of days because its crank sensor was dirty and it was keeping the engine from sparking like it should. after I cleaned it and reinstalled it the car sprung back to life

he said it ran, just shut it off and wouldnt restart. crank sensor isnt the problem here

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I know a lot about cars. I can look at a car's headlights and tell you exactly which way it's coming